As a semiconductor device (non-volatile semiconductor memory device) capable of retaining stored data even after a power source is turned off, a semiconductor device including a floating gate has been known. Such a semiconductor device can write and erase stored date by accumulating and discharging electric charges into and from the floating gate.
For example, Japanese Patent Application Laid-Open Publication No. 2008-251825 (Patent Document 1) discloses a non-volatile semiconductor memory device including a floating gate and an NSG spacer formed thereon.